Radiation therapy involves medical procedures that selectively expose certain areas of a human body, such as cancerous tumors, to high doses of radiation. The intent of the radiation therapy is to irradiate the targeted biological tissue such that the harmful tissue is destroyed. During a radiation therapy, a radiation source may be rotated around a patient to deliver radiation from different angles at target region inside the patient. The radiation source may be mounted on an arm or a ring gantry. In certain radiation therapy, the patient support supporting the patient may also be moved. Despite careful treatment planning, during a medical procedure, a collision may occur between a moving part of a medical device and a patient. For example, the gantry of the radiation machine and the patient may possibly collide during radiation therapy. As the dose delivery plans become more complex, the combination of a rotating gantry during treatment and couch movement for non-coplanar beams delivery has increased the chance of collisions.
While gantry mounted laser guard system and room mounted scanners have been used to detect possible collisions, these methods have disadvantages. While a gantry mounted laser guard system has the ability to detect when a plane defined by laser scanning is intersected by an intruding object, it does not work in many situations where the couch is rotated.
In the case of a room-based scanning system, a room mounted scanner creates a profile of the patient on the couch and the profile is added to the knowledge base of the machine with software that keeps track of machine parts movement. A room-based scanning system is model-based and thus requires that the model be updated with every couch movement. In addition, from certain angles the scanner may not be able to re-profile the patient.
Applicant of the subject application determines that it may be desirable to develop a collision avoidance system that functions irrespective of the position and movement of the couch and other parts of the medical device.